My daughter's belly button stump fell off when she was around 9 days old. But it still stinks. It is not red or anything and isn't oozing. My husband just thinks it is still healing underneath.
When you clean it clean deeper if you can. I didnt relize i wasnt cleaning DS deep enough and my aunt got a whole bunch of lint out and it stopped stinking.
My pediatrician told us to clean it with alcohol if we noticed a smell. But I would definitely call and ask for advice. They may want to clean it up a bit for you, which they did for my LO.
With my first baby, his bellybutton wasn't healing right and smelled (bacteria). The pedi used a cauterizing stick to burn inside his bellybutton, but it didn't hurt him at all. DS didn't even flinch. Pedi told me to keep it dry, not give him a bath (sponge bath only) for a week to let it fully dry. We never had any issues after that.
Re: 3 1/2 week old belly button stinks
Have you cleaned that area?